Abstract/Summary

The physical characteristics of surface sediments from a suite of pristine lakes on Signy Island, maritime Antarctic,
were used to develop a quantitative link between catchment ice-extent and lake-sediment response. Percentage dry
weight, median particle size, percentage loss-on-ignition and wet density of the lakes’ surface sediments were the
most significant variables explaining contemporary catchment ice-extent. Two independent reconstruction models
– Partial Least Squares (PLS) and a Modern Analog Technique (MAT) – were applied to dated sediment cores at two
sites on Signy Island. The validity of the reconstructions was tested against historical information on catchment
ice-extent. With sufficiently high sedimentation rates and sampling resolution, the models can predict sub-decadal
changes in ice-extent. The model results are best regarded as indicators of erosion resulting from meltwater activity
in the catchment. Comparison of results with Twentieth Century climate records affirms the hypothesis that climatic
warming is the most likely cause for the ice retreat observed on Signy Island during the last 40 yrs. Similar reconstruction models using these simple sedimentary measures could be developed for analogous locations in the Antarctic and in Arctic and Alpine regions.